Hernani Mota de Lima

Plano de recuperação de áreas degradadas versus plano de fechamento de mina: um estudo comparativo

This paper reports the results of an analysis of 20 Plans for Rehabilitation of Degraded Areas (PRADs) prepared for mines located in the Iron Quadrangle (MG) in accordance with the Decree no 97.632, dated April 10th of 1989. Usually PRAD has been understood as a mine closure plan. Therefore, the objective of this study was to check PRADs contents and compliance with the Norm NBR 13030 - “Elaboration and Presentation of rehabilitation project for impacted areas by mining”, as well as, to compare its contents with a mine closure plan, in order to establish similarities and differences between them. This work presents the results of this comparative analysis; highlights the environmental, socio-economic and cultural risks of taking a PRAD as a mine closure plan; shows the necessity of differing PRAD from a mine closure plan and stresses the requirements’ overlap for mine companies.

Desenvolvimento sustentável e garimpo: o caso do Garimpo do Engenho Podre em Mariana, Minas Gerais

Based on sustainable development principles, this paper evaluates artisanal gold mining activity in Engenho Podre. This study followed the hypothesis that the implementation of environmental management according to a conduct adjustment agreement firmed by the Cooperativa dos Garimpeiros de Mariana (COOPERGAMA), associated with operational performance improvement would permit continuation of this activity in a sustainable way from the environmental, socioeconomic and cultural point of view. Although still illegal, from the technical point of view, the artisanal mining at Engenho Podre is adopting environmentally-accepted strategies to promote reasonable socioeconomic development. However, administrative issues and lack of investments still affect the sustainability of such practices in the long-term. This paper shows that when good administrative and environmental practices are adopted, it is possible to meet the sustainable development principles in an artisanal mining activity.

Análise do plano de fechamento de mina no plano de aproveitamento econômico de uma jazida - uma exigência da NRM-20.

The Brazilian Mining Code defines mining as the set of operations required for the industrial exploitation of a mineral deposit, which includes mining and processing. In order to obtain a Mining Permit, such operations should be presented in an Economic Exploitation Plan (EEP) which should demonstrate the technical and economic feasibility of mining a deposit. Since 2002, the inclusion of a mine closure plan in the EEP has been a requirement, as the NRM-20. This study investigated the applicability of this requirements inclusion in the EEP from proposals presented to DNPM. Thirty EEPs were analyzed after the publication of the NRM. Although it is a requirement of NRM-20, this study demonstrates that no one of the studied mines had a closure plan included in the EEP, or thereafter, as an update. And, that those EEPs were approved and the mining permit granted. Even with no closure plans included, 14 EEPs presented some closure cost for economic analysis. In these, the Estimated Closure Cost (ECC) had greatly dispersed values. On the other hand, in 16 EEPs there was no cost estimate associated with mine closure. This study highlights the lack of government guidelines for the evaluation of EEPs focused on a mine closure plan. And, that the mining companies fail to consider the hiring of consultants for closure plan design as a mine closure cost.

Análise das concessões de lavra quanto às suspensões temporárias de operação

This paper reports the results of analysis of exploitation consents in the Minas Gerais State. The objective this study was map the exploitation consents granted in the State, in order to classify the existing processes in the Mining Cadastre in: active mines, mines with suspension of extraction registered in the National Department of Mineral Production and mines with suspension of extraction published in the Official Gazette. The results showed that there 1.739 consents in the State, where the mines with temporary suspension of extraction added 234 mines. This work presents the results of this analysis and highlights the absence and the need of the development and implementation of a mine closure policy and control and enforcement on dealing with mines on temporary suspension status as well as abandoned ones.

Mission-critical mobile broadband communications in open-pit mines

The need for continuous safety improvements and increased operational efficiency is driving the mining industry through a transition toward automated operations. From a communications perspective, this transition introduces a new set of high-bandwidth business-critical and mission- critical applications that need to be met by the wireless network. This article introduces fundamental concepts behind open-pit mining and discusses why this ever-changing environment and strict industrial reliability requirements pose unique challenges to traditional broadband network planning and optimization techniques. On the other hand, unlike unpredictable disaster scenarios, mining is a carefully planned activity. Taking advantage of this predictability element, we propose a framework that integrates mine and radio network planning so that continuous and automated adaptation of the radio network becomes possible. The potential benefits of this framework are evaluated by means of an illustrative example.

Cumulative impact assessment on air quality from multiple open pit mines

Both open pit mine and smelter projects can have significant impacts on a variety of environmental resources. Among these, air quality of the surroundings is a key issue. Additionally, the environmental assessment of projects demands integrated approach taking in account all pollution sources. Therefore, specific focus has been put on the methodology for assessing impacts on air quality. This paper proposes an integrated index of environmental impact aiming to quantify the air quality impact of industrial operations around an urban area, in case of scarcity of in situ acquired data. This proposed pollution index is demonstrated by a case study conducted in the municipality of Congonhas, Brazil, in which contributions of five open pit mines and two smelters were studied. To achieve the pollution index, the wind rose and distances from the centroids of effective areas to the urban nucleus itself were considered, taking into account the wind projection areas from windward impacting sources on the leeward impacted urban site. The proposed index also includes the squared wind speed (proportional to the kinetic energy transferred in uplifting dust from ground surface). The method proposed is considered suitable for impact assignment for each one of the air pollution sources in the neighborhood of studied area. Some fluid dynamic aspects of airborne particulate matter are also studied by proposing a new equation for threshold saltation speed.

Study of non-conventional fuels for explosives mixes

The use of ammonium nitrate and fuel oil (ANFO) results in low cost blasting. Such costs may be further reduced by replacing fuel oil with alternative fuels such as biomass (biodiesel, rice straw, corn cob, sugar cane bagasse) and tires residue. This paper investigates the use of other fuels instead of fuel oil by measuring the detonation velocity (VOD) and verifying the importance of these fuels in an explosive mixture. Except for biodiesel, all the tests conducted for the mixture of ammonium nitrate and alternative fuels showed poor performance when compared with ANFO. The achieved percentage of detonation velocity (VOD) of the mixtures in relation to the ANFO were 55.4% for ammonium nitrate + rice straw, 64.9% for ammonium nitrate + corn cob, 70.1% for ammonium nitrate + sugar cane bagasse, 74.4% for ammonium nitrate + tires residue and 93.7% for ammonium nitrate + biodiesel. This study indicates that the methodology proposed can be applied as a reference for determination and preparation of explosive mixtures of fuel and oxidizing agents since in all the tests conducted the detonation of the charges occurred.

Las Zeolitas y su Aplicación en la Descontaminación de Efluentes Mineros

En este articulo se presenta la genesis, la estructura y la clasificacion de las zeolitas naturales. Se describen las propiedades mas relevantes de las mismas, tales como porosidad, adsorcion e intercambio ionico. Se revisan los usos de las zeolitas naturales en el tratamiento de efluentes conteniendo metales pesados segun la literatura vigente. Dichos usos estan enfocados hacia el tratamiento de efluentes minero-metalurgicos y la contaminacion por mercurio en actividades mineras informales. El estudio muestra que las zeolitas naturales son eficientes en la remocion de metales pesados en efluentes minero metalurgicos, pueden ser producidas y beneficiadas a bajo costo, y pueden ser usadas tambien para la adsorcion de vapores de mercurio en hornos de copelas quemadores de amalgama.

Diagnóstico dos garimpos de topázio imperial no Alto Maracujá, Sub-bacia do rio das Velhas, MG

This study presents a diagnosis of the imperial topaz artisanal mining (garimpo) at the head of Maracuja river, called high Maracuja, Cachoeira do Campo, district of Ouro Preto, Minas Gerais. Operating in this region for a long time, the garimpo is accused of seriously affecting the infrastructure and the environment of the region with emphasis on natural drainage and levees forest impacts. To conduct the environmental diagnosis of the garimpos activity in the region it was used environmental assessment techniques, field trips, interviews, historic literature research and GPS survey of the garimpos. This study presents the effects on the environment and infrastructure as well as the socioeconomic interaction of this activity in the region.

Dimensionamento estrutural de estradas de mina a céu aberto

An unpaved mine haul road, based on CBR and DNER empirical methods, was designed using materials which are typical in current Brazilian iron ore mining. By means of the mechanistic-empirical structural ELSYM5 software, the results obtained by previous methods were compared and an optimization of the DNER design was proposed. The results demonstrate that the total thickness of the pavement calculated by the two methods is basically the same and that the base layer thickness calculated by the DNER method is superior to the one obtained by the CBR method, whereas the opposite occurs in relation to the sub-base. Both designs show through the application of ELSYM5 software that they are not the most appropriate, since the strain of some layers, especially in the CBR case, is above the acceptable limit of 2000 µe. Analyzing the variation of the layers thickness, it was possible to obtain an adequate design, which led to the reduction of the total pavement layer thickness from 1.97 m to 1.40 m. The reduction of the layers strain in which the elastic modulus was submitted to variation, demonstrates the importance of performing tests for the physical characterization of materials.